Secondary battery head cover assembly, secondary battery including the same and assembling method thereof

ABSTRACT

The present application relates to a secondary battery, including a naked battery core and a secondary battery head cover assembly. The secondary battery head cover assembly includes a head cover and an insulation structure. The insulation structure includes a top connection sheet and two naked battery core insulation sheets, and the two naked battery core insulation sheets are connected to two long sides of the top connection sheet, respectively. The top connection sheet is located below the head cover. The naked battery core is located below the top connection sheet. The head cover is provided with an explosion-proof valve, the top connection sheet is provided with an explosion-proof valve air hole, and the explosion-proof valve air hole is provided correspondingly below the explosion-proof valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. applicationSer. No. 15/349,931, filed on Nov. 11, 2016, which claims priority toChinese Patent Application No. 201610181816.8, filed on Mar. 28, 2016,the content of which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present application relates to the technical field of secondarybattery production and, more particularly, to a secondary battery headcover assembly, a secondary battery including the same and an assemblingmethod thereof.

BACKGROUND

Insulation sheet is typically provided in a secondary battery, which caneffectively prevent side walls and bottom surface of the naked batterycore from contacting with housing of the secondary battery.

In the related art, the secondary battery is typically formed as aconnection structure by buckling a top bracket on each long side of thehead cover, respectively, and protruding a lower plastic of an electrodepole downward from a short side of the head cover to be parallel andlevel with the top bracket. During assembly, the naked battery core isfirst assembled with the above connection structure by connecting with atop connection sheet. Then, the naked battery core insulation sheet goesupward gradually from the bottom of the naked battery core to wrap aside wall of the naked battery core, and finally, is hot-melt connectedwith the top bracket and the lower plastic.

In such a connection structure, however, both the lower plastic and thetop bracket need to protrude downward a certain distance along the headcover, and therefore, when assembled, a certain height space needs to beoccupied, which is undesired for simplifying the assembling process andimproving the capacity of the battery.

SUMMARY

The present application provides a secondary battery head coverassembly, a secondary battery including same and an assembling methodthereof, and is capable of improving capacity of the secondary battery.

In a first aspect of the present application, a secondary battery headcover assembly is provided, including a head cover and an insulationstructure, wherein the insulation structure comprises a top connectionsheet and two naked battery core insulation sheets, and the two nakedbattery core insulation sheets are connected to two long sides of thetop connection sheet, respectively,

an electrode pole is provided on the head cover, and an electrode polethrough hole is provided at a position on the top connection sheetcorresponding to the electrode pole, the top connection sheet is locatedbelow the head cover and is connected to the head cover.

Preferably, at least one connecting hole for connecting to the headcover is provided on the top connection sheet, at least one connectingpiece is provided on a lower surface of the head cover, and theconnecting piece is fitted with and connected to the connecting hole.

Preferably, the connecting piece is a riveting piece or an engagingpiece.

Preferably, a lower plastic is provided on the head cover, and the topconnection sheet is fixed with the lower plastic by hot melt.

Preferably, the top connection sheet and the two naked battery coreinsulation sheets are integrated as a whole.

Preferably, the head cover is further provided with at least one of aliquid injection hole, an explosion-proof valve, and a reversing sheet,and the top connection sheet is further provided with at least one of aliquid injection through hole, an explosion-proof valve air hole, and areversing sheet air hole,

wherein, the liquid injection through hole is provided correspondinglybelow the liquid injection hole, the explosion-proof valve air hole isprovided correspondingly below the explosion-proof valve, and thereversing sheet air hole is provided correspondingly below the reversingsheet.

Preferably, the electrode pole passes through the electrode pole throughhole,

In a second aspect of the present application, a secondary battery isprovided, including a naked battery core and the secondary battery headcover assembly as described above,

the naked battery core is located below the top connection sheet, andthe two naked battery core insulation sheets wrap side and bottomsurfaces of the naked battery core.

Preferably, the naked battery core insulation sheet includes: a maininsulation region directly connected with the top connection sheet, aside insulation region formed by extending the main insulation regionoutward along two lateral sides perpendicular to the long side, and abottom insulation region formed by extending the main insulation regionoutward along a side away from the top connection sheet, wherein thebottom insulation region is provided with an electrolyte permeationhole,

the two main insulation regions cover two main side surfaces of thenaked battery core, respectively, the side insulation region covers anarrow side surface of the naked battery core, the bottom insulationregion covers a bottom surface of the naked battery core, the sideinsulation regions being located on different naked battery coreinsulation sheets which cover the same side of the naked battery coreare connected with each other, and the two bottom insulation regions arealso connected with each other.

Preferably, the battery further includes a chassis plate, wherein thechassis plate is fixedly attached to a surface of one of the bottominsulation regions.

Preferably, the two naked battery core insulation sheets have consistentstructures.

Preferably, crease lines are provided at a junction between the maininsulation region and the side insulation region, and at a junction of ajunctional region between the main insulation region and the bottominsulation region.

Preferably,

the side insulation regions located on different naked battery coreinsulation sheets which cover the same side of the naked battery coreare connected with each other by hot melting,

and/or

the two bottom insulation regions are connected with each other by hotmelting.

In a third aspect of the present application, an assembling method ofthe secondary battery is provided, including steps as follows:

fixing the top connection sheet to the head cover;

welding the naked battery core and the head cover; and

wrapping the side and bottom surfaces of the naked battery core by thenaked battery core insulation sheet.

In a fourth aspect of the present application, a secondary battery isprovided. The secondary battery includes a naked battery core and asecondary battery head cover assembly. The secondary battery head coverassembly includes a head cover and an insulation structure. Theinsulation structure includes a top connection sheet and two nakedbattery core insulation sheets, and the two naked battery coreinsulation sheets are connected to two long sides of the top connectionsheet, respectively. The top connection sheet is located below the headcover. The naked battery core is located below the top connection sheet.The head cover is provided with an explosion-proof valve, the topconnection sheet is provided with an explosion-proof valve air hole, andthe explosion-proof valve air hole is provided correspondingly below theexplosion-proof valve.

Preferably, the two naked battery core insulation sheets cover the nakedbattery core.

Preferably, the two naked battery core insulation sheets have consistentstructures.

Preferably, each of the two naked battery core insulation sheetsincludes a main insulation region directly connected with the topconnection sheet, and the two main insulation regions cover two mainside surfaces of the naked battery core, respectively.

Preferably, the two main insulation regions completely cover the twomain side surfaces of the naked battery core, respectively.

Preferably, each of the two naked battery core insulation sheetsincludes a side insulation region formed by extending the maininsulation region outward along two lateral sides perpendicular to thelong side, and a bottom insulation region formed by extending the maininsulation region outward along a side away from the top connectionsheet, wherein the bottom insulation region is provided with anelectrolyte permeation hole. The side insulation region covers a narrowside surface of the naked battery core, and the bottom insulation regioncovers a bottom surface of the naked battery core.

Preferably, the top connection sheet is connected with the head cover.

Preferably, an electrode pole is provided on the head cover, and anelectrode pole through hole is provided at a position on the topconnection sheet corresponding to the electrode pole.

Preferably, the head cover is further provided with a liquid injectionhole, and the top connection sheet is further provided with a liquidinjection through hole. The liquid injection through hole is providedcorrespondingly below the liquid injection hole.

Preferably, the top connection sheet and the two naked battery coreinsulation sheets are integrated as a whole.

Preferably, the head cover is further provided with a reversing sheet,and the top connection sheet is further provided with a reversing sheetair hole. The reversing sheet air hole is provided correspondingly belowthe reversing sheet,

The technical solutions provided by the present application have thefollowing beneficial effects that:

By connecting the top connection sheet with the head cover, thesecondary battery head cover assembly provided by the presentapplication changes the original assembling method, there is no need toprovide a top bracket any more, thus saving internal space of thesecondary battery and improving energy density.

It should be understood that both the foregoing general description andthe following detailed description are only illustrative, which are notintended to limit the present application.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a structural schematic diagram of a secondary batteryaccording to an embodiment of the present application after a housing isremoved;

FIG. 2 is a structural schematic diagram of assembling a secondarybattery head cover assembly according to an embodiment of the presentapplication;

FIG. 3 is an exploded structural schematic diagram of an insulationstructure with a hot melt region on a top connection sheet according toan embodiment of the present application;

FIG. 4 is an exploded structural schematic diagram of an insulationstructure with a connecting hole on a top connection sheet according toan embodiment of the present application; and

FIG. 5 is a partial cross-sectional structural schematic diagram of asecondary battery according to an embodiment of the present application.

REFERENCE NUMERALS

10-insulation structure;

100-top connection sheet;

100 a-electrode pole through hole;

100 b-explosion-proof valve air hole;

100 c-liquid injection through hole;

100 d-hot melt region;

100 e-connecting hole;

100 f-reversing sheet air hole;

101-naked battery core insulation sheet;

101 a-main insulation region;

101 b-side insulation region;

101 c-bottom insulation region;

101 d-electrolyte permeation hole;

101 e-crease line;

102-chassis plate;

20-head cover;

200-connecting piece;

30-naked battery core.

The accompanying drawings, which are incorporated herein and constitutea part of this specification, illustrate the embodiments of the presentapplication and, together with the specification, serve to explain theprinciples of the present application.

DESCRIPTION OF EMBODIMENTS

The present application will be further described in detail withreference to the drawings in combination with the detailed embodiments.Expressions, such as front, rear, left, right, up and down describedherein are all with reference to a placement state of the secondarybattery head cover assembly in the drawings.

As shown in FIG. 1, embodiments of the present application provide asecondary battery, including a secondary battery head cover assemblyhaving an insulation structure 10 and a head cover 20, and furtherincluding several major components such as a naked battery core 30 and ahousing (not shown). Particularly, the head cover 20, together with thehousing, defines a closed cavity in which the naked battery core 30 isplaced. The head cover 20 is provided with an electrode pole, and mayalso be provided with conventional structures such as an explosion-proofvalve, a liquid injection hole and a reversing sheet.

The secondary battery head cover assembly 10 is to prevent most of theareas on the naked battery core 30 from contacting with the inner wallof the closed cavity, as shown from FIG. 2 to FIG. 4, it specificallyincludes a top connection sheet 100 and two naked battery coreinsulation sheets 101. The top connection sheet 100 is located below thehead cover 20 and is fixed to the head cover 20, on one hand, the topconnection sheet 100 serves as a connection structure between thesecondary battery head cover assembly 10 and the head cover 20, on theother hand, it can also be used to isolate most of the areas on topportion of the naked battery core 30 from the head cover 20, andtherefore, the top connection sheet 100 only provides respective runoutstructures such as electrode pole through hole 100 a, explosion-proofvalve air hole 100 b, liquid injection hole 100 c and a reversing sheetair hole 100 f corresponding to positions of the electrode pole, theexplosion-proof valve, the liquid injection hole and the reversingsheet, and the remaining areas are integrated isolation structures. Whenthe top connection sheet 100 is connecting to the head cover 20, anelectrode pole of the head cover will pass through the electrode polethrough hole 100 a, the liquid injection through hole 100 b is providedcorrespondingly below the liquid injection hole, the explosion-proofvalve air hole 100 c is provided correspondingly below theexplosion-proof valve, the explosion-proof valve air hole 100 c can havea shape substantially the same with the explosion-proof valve (refer toFIG. 3), and can also be made as a screen shape (refer to FIG. 4), andthe reversing sheet air hole 100 f is also provided correspondinglybelow the reversing sheet.

The two naked battery core insulation sheets 101 are connected to twolong sides of the top connection sheet 100, respectively, for wrappingthe main side surface, the narrow side surface and the bottom of thenaked battery core 30. The top connection sheet 100 is preferablyintegrally formed with the two naked battery core insulation sheets 101.

As shown in FIG. 3 and FIG. 4, the naked battery core insulation sheet101 specifically includes a main insulation region 101 a, a sideinsulation region 101 b and a bottom insulation region 101 c. The maininsulation region 101 a is in direct connection with a long side of thetop connection sheet 100, the naked battery core 30 is located below thetop connection sheet 100, and the main insulation region 101 a can coverthe main side surface of the naked battery core 30 after being bendeddownward at an angle of 90 degrees at a junction thereof. The sideinsulation region 101 b is formed by extending the main insulationregion 101 a outward along two lateral sides perpendicular to the longside, and can cover the narrow side surface of the naked battery core 30after being bended to the interior of the naked battery core 30 at anangle of 90 degrees at a junction thereof The bottom insulation region101 c is formed by extending the main insulation region 101 a outwardalong a side away from the top connection sheet 100, and can cover thebottom surface of the naked battery core 30 after being bended to theinterior of the naked battery core 30 at an angle of 90 degrees at ajunction thereof. In order to smoothly let the electrolyte contact withthe naked battery core, the bottom insulation region 101 c is alsoprovided with an electrolyte permeation hole 101 d. In the presentembodiment, the top connection sheet 100 and two naked battery coreinsulation sheets 101 need to have a good bending property, so as towrap the naked battery core 30. To this end, crease lines 101 e areprovided at a junction between the main insulation region and the sideinsulation region, and at a junction of a junctional region between themain insulation region and the bottom insulation region, the thicknessof the crease line 101 e can be thinner than other areas, so as toprovide a more excellent bending capability, generally, the width of thecrease line 101 e can be kept around 0.2 mm.

The secondary battery provided in the present embodiment adopts theassembling method as follows:

Step one, fixing the top connection sheet 100 to the head cover 20(refer to FIG. 2). Here, a number of fixed manners can be adopted, forexample, the top connection sheet 100 and the lower plastic on the headcover can be fixed directly together by means of hot melting or welding.As shown in FIG. 3, when such manner is adopted, the hot melt region 100d is preferred to be uniformly distributed on the top connection sheet100. As shown in FIG. 4, a connecting piece 200, such as a riveted pieceor an engaged piece, can also be provided on the lower surface of thehead cover 20, and a connecting hole 100 e corresponding to theconnecting piece 200 is provided on the top connection sheet 100,subsequently, the connecting piece 200 is fitted with the connectinghole 100 e, such as by riveting or buckling (refer to FIG. 5), as so toachieve the connection between the top connection sheet 100 and the headcover 20.

Step two, welding the naked battery core 30 with the head cover 20.Here, the head cover 20 and the top connection sheet 100 are placedtogether on top of the naked battery core 30, subsequently, weldingcorresponding parts of the naked battery core 30 and the head cover 20together, the corresponding parts mainly are an electrode tab and theelectrode pole.

Step three, wrapping the side wall and the bottom surface of the nakedbattery core 30 with the naked battery core insulation sheet 101. Inthis step, firstly, there is a need to bend the main insulation region101 a, the side insulation region 101 b and the bottom insulation region101 c to different positions, respectively. In particular, bending thetwo main insulation regions 101 a from the junction with the topconnection sheet 100 downward at an angle of approximate 90 degrees,bending the side insulation region 101 b connected with each maininsulation region 101 a at an angle of 90 degrees towards the oppositeside, bending the two bottom insulation regions 101 c at an angle of 90degrees towards the top connection sheet 100, and finally, wrapping theside surface and the bottom surface of the whole naked battery core 30substantially.

Step four, connecting the side insulation regions 101 b located ondifferent naked battery core insulation sheets 101 which cover the sameside of the naked battery core 30 with each other, and also connectingthe two bottom insulation regions 101 c with each other. During theconnection, the side insulation regions 101 b can be connected firstly,or the two bottom insulation regions 101 c can be connected firstly, theconnecting manner is generally hot melt welding, besides, in order toimprove the overall connection strength, the welding region is alsopreferred to be uniformly distributed.

In terms of each naked battery core insulation sheet 101, the sideinsulation region 101 b and bottom insulation region 101 c on one nakedbattery core insulation sheet may differ from the side insulation region101 b and bottom insulation region 101 c on another naked battery coreinsulation sheet, as long as the narrow side surface and the bottomsurface of the naked battery core 30 can be completely covered, andsufficient hot melt regions are left. To facilitate manufacturing, thetwo naked battery core insulation sheets 101 are preferred to haveconsistent structures.

The weight of the naked battery core 30 mainly concentrates on thebottom surface, and therefore, the bottom insulation region 101 c willbear major force. As a result, the hot melt region of the bottominsulation region 101 c tends to be disengaged or the bottom insulationregion 101 c is damaged on the whole. To prevent the bottom insulationregion 101 c from being disengaged or damaged, the secondary batteryhead cover assembly 10 in the present embodiment also includes a chassisplate 102. The chassis plate 102 can be made from materials with higherstrength, prior to assembly, the chassis plate is fixedly attached to asurface on any of the bottom insulation regions 101 c, here, thestructure of the chassis plate 102 and the attaching position should bedesigned carefully, so as not to shield the electrolyte permeation hole101 d. Generally, the fixing is generally done by hot melting, severalhot melt regions with a fixed spacing on the chassis plate 102 are left,and meanwhile, hot melt regions are also left on corresponding positionson the bottom insulation region 101 c to be attached, then, the hot meltregion is welded by hot melting correspondingly.

During the process of wrapping the naked battery core 30, the bottominsulation region 101 c without connecting to the chassis plate 102 islocated at the inner side, the bottom insulation region 101 c attachedwith the chassis plate 102 is located in the middle, and the chassisplate 102 is located at the bottom-most part. By means of the higherstrength of the chassis plate 102, the bottom insulation region 101 ccan effectively be prevent from severe local deformation under theaction of the naked battery core 30, and thus prevent the bottominsulation region 101 c from being disengaged or damaged.

By changing the structure and the assembling method, the presentembodiment saves internal space of the secondary battery, so as toimprove energy density.

Described above are merely preferred embodiments of the presentapplication, which are not intended to limit the present application,various modifications and variations will be apparent to persons skilledin the art. Any modification, equivalent replacement, improvement, etc.made without departing from the spirit and principle of the presentapplication shall fall within the protection scope of the application.

What is claimed is:
 1. A secondary battery, comprising a naked batterycore arid a secondary battery head cover assembly, wherein the secondarybattery head cover assembly comprises a head cover and an insulationstructure, wherein the insulation structure comprises a top connectionsheet and two naked battery core insulation sheets, and the two nakedbattery core insulation sheets are connected to two long sides of thetop connection sheet, respectively, the top connection sheet is locatedbelow the head cover, and the naked battery core is located below thetop connection sheet, and the head cover is provided with anexplosion-proof valve, the top connection sheet is provided with anexplosion-proof valve air hole, and the explosion-proof valve air holeis provided correspondingly below the explosion-proof valve.
 2. Thesecondary battery according to claim 1, wherein, the two naked batterycore insulation sheets cover the naked battery core.
 3. The secondarybattery according to claim 1, wherein, the two naked battery coreinsulation sheets have consistent structures.
 4. The secondary batteryaccording to claim 2, wherein, each of the two naked battery coreinsulation sheets comprises a main insulation region directly connectedwith the top connection sheet, and the two main insulation regions covertwo main side surfaces of the naked battery core, respectively.
 5. Thesecondary battery according to claim 4, wherein, the two main insulationregions completely cover the two main side surfaces of the naked batterycore, respectively,
 6. The secondary battery according to claim 4,wherein, each of the two naked battery core insulation sheets comprisesa side insulation region formed by extending the main insulation regionoutward along two lateral sides perpendicular to the long side, and abottom insulation region formed by extending the main insulation regionoutward along a side away from the top connection sheet, wherein thebottom insulation region is provided with an electrolyte permeationhole, and the side insulation region covers a narrow side surface of thenaked battery core, and the bottom insulation region covers a bottomsurface of the naked battery core.
 7. The secondary battery according toclaim 1, wherein, the top connection sheet is connected with the headcover.
 8. The secondary battery according to claim 1, wherein, anelectrode pole is provided on the head cover, and an electrode polethrough hole is provided at a position on the top connection sheetcorresponding to the electrode pole.
 9. The secondary battery accordingto claim 1, wherein, the head cover is further provided with a liquidinjection hole, and the top connection sheet is further provided with aliquid injection through hole, and wherein, the liquid injection throughhole is provided correspondingly below the liquid injection hole. 10.The secondary battery according to claim 1, wherein, the top connectionsheet and the two naked battery core insulation sheets are integrated asa whole.
 11. The secondary battery according to claim 1, wherein, thehead cover is further provided with a reversing sheet, and the topconnection sheet is further provided with a reversing sheet air hole,and wherein, the reversing sheet air hole is provided correspondinglybelow the reversing sheet.